1. Field-of the Invention
The present invention generally relates to ejection of cargo from projectiles and, more particularly, is concerned with a projectile base plug having enhanced drag-producing separation capability to assure the ejected base plug moves away from the ejected cargo and also prevents mid-air collisions therebetween.
2. Description of the Prior Art
Cargo such as submunitions, mines and canisters are typically delivered to a target zone by projectiles spinning and travelling along a ballistic trajectory path. In the usual sequence of operations, an explosive charge placed in a cylindrical carrier of the projectile in front of the cargo therein is ignited by a time-of-flight fuze when the projectile reaches a desired point along its trajectory path above the target zone. The gas pressure generated by ignition of the charge pushes rearwardly against the cargo to dislodge and eject a projectile base plug from the rear end of the carrier and eject the cargo from the projectile.
Mid-air collisions between the base plug and cargo expelled from the projectile can cause damage to the cargo. These collisions are due to close proximity between the ejected base plug and cargo. When the diameter of the cargo is comparable to that of the base plug, aerodynamic effects act to keep the ejected base plug in the wake of the cargo, thus preventing drag forces from moving the spinning and wobbling base plug away from the cargo. In some cases, the base plug fits over the cargo and a positive separation force between base and cargo is necessary.
Current arrangements to enhance base plug separation use spin axis transfer or an unbalanced split base plug to cause base plug travel perpendicular to the flight path of the cargo. Several problems exist with these approaches. One problem is that the flight path of the projectile can be disturbed at the critical moment of ejection. Another problem concerns safety at the test range since the unpredictable cross-range trajectory of the base plug severely limits the choice of camera locations at the ejection site.
Consequently, a need exists for a different approach to produce base plug separation from the cargo which avoids the aforementioned problems.